/*
 * usb_i2c.h
 *
 *  Created on: 2020-10-03 08:50
 *      Author: Jack Chen <redchenjs@live.com>
 */

#ifndef INC_USER_USB_I2C_H_
#define INC_USER_USB_I2C_H_

#include <stdint.h>

/* commands from USB, must match command ids in the kernel driver */
#define CMD_ECHO            0
#define CMD_GET_FUNC        1
#define CMD_SET_DELAY       2
#define CMD_GET_STATUS      3

#define CMD_I2C_IO          4
#define CMD_I2C_IO_BEGIN    (1<<0)
#define CMD_I2C_IO_END      (1<<1)

/* i2c address ack status */
#define STATUS_IDLE         0
#define STATUS_ADDRESS_ACK  1
#define STATUS_ADDRESS_NACK 2

/**
 * struct i2c_msg - an I2C transaction segment beginning with START
 * @addr: Slave address, either seven or ten bits.  When this is a ten
 * bit address, I2C_M_TEN must be set in @flags and the adapter
 * must support I2C_FUNC_10BIT_ADDR.
 * @flags: I2C_M_RD is handled by all adapters.  No other flags may be
 * provided unless the adapter exported the relevant I2C_FUNC_*
 * flags through i2c_check_functionality().
 * @len: Number of data bytes in @buf being read from or written to the
 * I2C slave address.  For read transactions where I2C_M_RECV_LEN
 * is set, the caller guarantees that this buffer can hold up to
 * 32 bytes in addition to the initial length byte sent by the
 * slave (plus, if used, the SMBus PEC); and this value will be
 * incremented by the number of block data bytes received.
 * @buf: The buffer into which data is read, or from which it's written.
 *
 * An i2c_msg is the low level representation of one segment of an I2C
 * transaction.  It is visible to drivers in the @i2c_transfer() procedure,
 * to userspace from i2c-dev, and to I2C adapter drivers through the
 * @i2c_adapter.@master_xfer() method.
 *
 * Except when I2C "protocol mangling" is used, all I2C adapters implement
 * the standard rules for I2C transactions.  Each transaction begins with a
 * START.  That is followed by the slave address, and a bit encoding read
 * versus write.  Then follow all the data bytes, possibly including a byte
 * with SMBus PEC.  The transfer terminates with a NAK, or when all those
 * bytes have been transferred and ACKed.  If this is the last message in a
 * group, it is followed by a STOP.  Otherwise it is followed by the next
 * @i2c_msg transaction segment, beginning with a (repeated) START.
 *
 * Alternatively, when the adapter supports I2C_FUNC_PROTOCOL_MANGLING then
 * passing certain @flags may have changed those standard protocol behaviors.
 * Those flags are only for use with broken/nonconforming slaves, and with
 * adapters which are known to support the specific mangling options they
 * need (one or more of IGNORE_NAK, NO_RD_ACK, NOSTART, and REV_DIR_ADDR).
 */
struct i2c_msg {
    uint16_t addr;          /* slave address */
    uint16_t flags;
#define I2C_M_RD            0x0001  /* read data, from slave to master */
                                    /* I2C_M_RD is guaranteed to be 0x0001! */
#define I2C_M_TEN           0x0010  /* this is a ten bit chip address */
#define I2C_M_DMA_SAFE      0x0200  /* the buffer of this message is DMA safe */
                                    /* makes only sense in kernelspace */
                                    /* userspace buffers are copied anyway */
#define I2C_M_RECV_LEN      0x0400  /* length will be first received byte */
#define I2C_M_NO_RD_ACK     0x0800  /* if I2C_FUNC_PROTOCOL_MANGLING */
#define I2C_M_IGNORE_NAK    0x1000  /* if I2C_FUNC_PROTOCOL_MANGLING */
#define I2C_M_REV_DIR_ADDR  0x2000  /* if I2C_FUNC_PROTOCOL_MANGLING */
#define I2C_M_NOSTART       0x4000  /* if I2C_FUNC_NOSTART */
#define I2C_M_STOP          0x8000  /* if I2C_FUNC_PROTOCOL_MANGLING */
    uint16_t len;           /* msg length */
    uint8_t *buf;           /* pointer to msg data */
};

/* To determine what functionality is present */
#define I2C_FUNC_I2C                    0x00000001
#define I2C_FUNC_10BIT_ADDR             0x00000002
#define I2C_FUNC_PROTOCOL_MANGLING      0x00000004  /* I2C_M_IGNORE_NAK etc. */
#define I2C_FUNC_SMBUS_PEC              0x00000008
#define I2C_FUNC_NOSTART                0x00000010  /* I2C_M_NOSTART */
#define I2C_FUNC_SLAVE                  0x00000020
#define I2C_FUNC_SMBUS_BLOCK_PROC_CALL  0x00008000  /* SMBus 2.0 */
#define I2C_FUNC_SMBUS_QUICK            0x00010000
#define I2C_FUNC_SMBUS_READ_BYTE        0x00020000
#define I2C_FUNC_SMBUS_WRITE_BYTE       0x00040000
#define I2C_FUNC_SMBUS_READ_BYTE_DATA   0x00080000
#define I2C_FUNC_SMBUS_WRITE_BYTE_DATA  0x00100000
#define I2C_FUNC_SMBUS_READ_WORD_DATA   0x00200000
#define I2C_FUNC_SMBUS_WRITE_WORD_DATA  0x00400000
#define I2C_FUNC_SMBUS_PROC_CALL        0x00800000
#define I2C_FUNC_SMBUS_READ_BLOCK_DATA  0x01000000
#define I2C_FUNC_SMBUS_WRITE_BLOCK_DATA 0x02000000
#define I2C_FUNC_SMBUS_READ_I2C_BLOCK   0x04000000  /* I2C-like block xfer  */
#define I2C_FUNC_SMBUS_WRITE_I2C_BLOCK  0x08000000  /* w/ 1-byte reg. addr. */
#define I2C_FUNC_SMBUS_HOST_NOTIFY      0x10000000

#define I2C_FUNC_SMBUS_BYTE             (I2C_FUNC_SMBUS_READ_BYTE | \
                                         I2C_FUNC_SMBUS_WRITE_BYTE)
#define I2C_FUNC_SMBUS_BYTE_DATA        (I2C_FUNC_SMBUS_READ_BYTE_DATA | \
                                         I2C_FUNC_SMBUS_WRITE_BYTE_DATA)
#define I2C_FUNC_SMBUS_WORD_DATA        (I2C_FUNC_SMBUS_READ_WORD_DATA | \
                                         I2C_FUNC_SMBUS_WRITE_WORD_DATA)
#define I2C_FUNC_SMBUS_BLOCK_DATA       (I2C_FUNC_SMBUS_READ_BLOCK_DATA | \
                                         I2C_FUNC_SMBUS_WRITE_BLOCK_DATA)
#define I2C_FUNC_SMBUS_I2C_BLOCK        (I2C_FUNC_SMBUS_READ_I2C_BLOCK | \
                                         I2C_FUNC_SMBUS_WRITE_I2C_BLOCK)

#define I2C_FUNC_SMBUS_EMUL             (I2C_FUNC_SMBUS_QUICK | \
                                         I2C_FUNC_SMBUS_BYTE | \
                                         I2C_FUNC_SMBUS_BYTE_DATA | \
                                         I2C_FUNC_SMBUS_WORD_DATA | \
                                         I2C_FUNC_SMBUS_PROC_CALL | \
                                         I2C_FUNC_SMBUS_WRITE_BLOCK_DATA | \
                                         I2C_FUNC_SMBUS_I2C_BLOCK | \
                                         I2C_FUNC_SMBUS_PEC)

/*
 * Data for SMBus Messages
 */
#define I2C_SMBUS_BLOCK_MAX     32      /* As specified in SMBus standard */
union i2c_smbus_data {
    uint8_t byte;
    uint16_t word;
    uint8_t block[I2C_SMBUS_BLOCK_MAX + 2]; /* block[0] is used for length */
                              /* and one more for user-space compatibility */
};

/* i2c_smbus_xfer read or write markers */
#define I2C_SMBUS_READ  1
#define I2C_SMBUS_WRITE 0

/* SMBus transaction types (size parameter in the above functions)
   Note: these no longer correspond to the (arbitrary) PIIX4 internal codes! */
#define I2C_SMBUS_QUICK             0
#define I2C_SMBUS_BYTE              1
#define I2C_SMBUS_BYTE_DATA         2
#define I2C_SMBUS_WORD_DATA         3
#define I2C_SMBUS_PROC_CALL         4
#define I2C_SMBUS_BLOCK_DATA        5
#define I2C_SMBUS_I2C_BLOCK_BROKEN  6
#define I2C_SMBUS_BLOCK_PROC_CALL   7       /* SMBus 2.0 */
#define I2C_SMBUS_I2C_BLOCK_DATA    8

#endif /* INC_USER_USB_I2C_H_ */
